Two Falcon 9s
A SpaceX Falcon 9 carrying a GPS 3 satellite stands at Space Launch Complex 40 (foreground) while another, carrying Starlink satellites, stands on nearby Launch Complex 39A. Both vehicles suffered last-second scrubs in launch attempts last week. Credit: SpaceX

WASHINGTON — Back-to-back last-second launch scrubs by two SpaceX Falcon 9 rockets 36 hours apart led Elon Musk to vow to undertake a “broad review” of launch operations in Florida in order to increase its launch rate.

The launch of a Falcon 9 carrying a GPS 3 satellite was scrubbed just two seconds before liftoff on the evening of Oct. 2 at Space Launch Complex 40 at Cape Canaveral Air Force Station. The company didn’t disclose the cause of the scrub during its webcast, but Musk later tweeted that the countdown stopped because of an “unexpected pressure rise in the turbomachinery gas generator.”

A day and a half earlier, the launch of another Falcon 9 carrying a set of Starlink satellites was stopped 18 seconds before liftoff at Launch Complex 39A at the Kennedy Space Center. The company said an “out-of-family ground sensor reading” prompted that abort. That launch has been rescheduled for the morning of Oct. 5, while SpaceX has not yet rescheduled the GPS 3 satellite launch.

The two scrubs clearly frustrated Musk. “We will need to make a lot of improvements to have a chance of completing 48 launches next year!” he wrote in a series of tweets a few hours after the second launch scrub.

He said the company would review all aspects of its operations to address those problems. “We’re doing a broad review of launch site, propulsion, structures, avionics, range & regulatory constraints this weekend,” he wrote. “I will also be at the Cape next week to review hardware in person.”

SpaceX hadn’t previously disclosed a goal of 48 launches a year in 2021, which would be roughly double the target set for this year. “You can probably look forward to two or so launches a month from us,” said Gwynne Shotwell, president of SpaceX, during a panel discussion at the Satellite 2020 conference in March. That total included both launches it performed for government and commercial customers as well as those for the company itself carrying Starlink satellites.

Forty-eight launches a year was also the target set several years ago by the U.S. Air Force for all users of the Eastern Range. That goal, dubbed “Drive to 48,” was intended to allow one launch a week as well as a pair of two-week maintenance periods.

“We continue to keep trying to increase our capacity,” said Maj. Gen. DeAnna M. Burt, director of operations and communications for the U.S. Space Force, at a Sept. 14 meeting of the Federal Aviation Administration’s Commercial Space Transportation Advisory Committee. That means moving away from what she called “old legacy systems” currently used for range operations to new approaches.

One such new approach is autonomous flight safety systems (AFSS) on vehicles that eliminate the need for many tracking and communications systems. SpaceX has implemented AFSS on its rockets, which has allowed it to schedule launches close together. On Aug. 30, SpaceX was prepared to perform two Falcon 9 launches the same day, one from each pad, although weather postponed one of the launches.

“Users like SpaceX have been leading the way on AFSS,” Burt said. All range users have to move to AFSS by October 2025 “or they need to find a way to fund the legacy range capabilities that will remain on the range if they require them.”

Earlier this year, SpaceX hinted at plans for a far higher launch rate from Florida. An environmental assessment published by the FAA in February projected the company performing up to 70 launches a year by 2023 from its two Florida launch sites. That included 10 Falcon Heavy launches.

Shotwell, though, asked about those figures at Satellite 2020, suggested that was an upper bound and not a forecast of actual launch activity. “We don’t have 10 Falcon Heavy missions to fly every year,” she said, noting the company picked a high number to encompass all possibilities for the environmental review. “We want to make sure we’re not cutting ourselves short.”

She hesitated to make predictions on launch rates in general, including for this year. “I don’t want to make predictions on how many launches we’re going to do this year, customer versus Starlink, because I’m always wrong,” she said. “But we’re busy.” SpaceX, though the first nine months of 2020, has completed 16 launches.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...